China’s PLA Air Force Incursion of Japan Airspace

Shaanxi Y9/KJ500 

On August 26, 2024, a Chinese military surveillance plane entered Japanese airspace, marking the first known incursion of the People’s Liberation Army Air Force into Japan’s territorial airspace. This airspace violation coincides with a period of growing geopolitical tensions between Japan and the People’s Republic of China and precedes National Security Advisor Jake Sullivan’s historic visit to China by a day.

Such an incursion, similar to those that the PLAAF conducts into the Taiwanese Air Defense Identification Zone, is a calculated tactic employed by China in order to maintain pressure and the initiative on both Japan and Taiwan. These kinds of operations enable China to maneuver itself into a favorable position and degrade the readiness and posture of its adversaries. This article evaluates the significance of the PLAAF’s violation of Japanese airspace given the context of the surrounding events relating to the deepening defense partnership between the US, Japan, and Taiwan and the PLA’s guiding strategy in conducting airspace incursions.

While Japan is not unaccustomed to foreign aircraft encroachment (the Japanese Self Defense Force scrambled fighters on 669 occasions in the last year alone, with 479 in response to the PLAAF), the fact that the PLAAF had outright violated Japanese airspace as opposed to toeing the boundary like in previous incidents points to this incident being a concerted act on the PRC’s part. The PLA, having operated and trained under the assumption that it would need to counterbalance the United States in a Taiwan contingency, now faces the possibility that the world’s third-largest economy, Japan, would also provide significant and sustained support for Taiwan in such a scenario. Recent events have demonstrated potential and actualized growing security cooperation between the United States, Japan, and Taiwan, cooperation that threatens the PRC’s nonnegotiable national security objective of reunifying Taiwan with the mainland.

In 2022, at the nudging of the United States, the JSDF underwent its most significant restructuring, posture shift, and expansion since the end of WWII. Japan’s National Defense Strategy stated outright that ““Taiwan is an extremely important partner and a precious friend of Japan, with whom Japan shares fundamental values… Peace and stability across the Taiwan Strait is an indispensable element for the security and prosperity of the international community.” The danger that the PRC poses to Taiwan then would eventually extend to Japan, and therefore, Japan has made preparations defend Taiwan accordingly. The encouragement of the US for Japanese militarization stems from the assessment that Japanese participation in a Taiwan contingency is a critical factor in whether or not Taiwan survives the encounter. This line of reasoning is especially apparent in the United States’ decision in July of 2024 to reconstitute its US Forces Japan as a joint force headquarters. With much of United States Indo-Pacific Command stationed in Hawaii and Alaska, the closest American units to Taiwan are US Forces Korea and US Forces Japan. USFK would be occupied maintaining the security in the Korean Peninsula, and so it would fall to USFJ to provide immediate assistance to Taiwan; thus, the restructuring of USFJ would facilitate a more effective response in an emergency.

Noting these developments, the PRC’s particular response of conducting airspace violations in both Taiwan and Japan have a two-fold aim. They are deliberately conducted to create stress, stress that would weaken the resolve to defend Taiwan, so that the PRC could potentially take Taiwan without fighting, and in the event that conflict does occur, degrade Taiwan and Japan’s ability to resist the PRC. A crucial component of the PLA’s guiding strategy is the concept of a conflict continuum, where military contention against foreign countries can take place below the threshold of outright war, and it is the PLA’s belief that it can conduct these gray zone activities to incrementally achieve its objectives while simultaneously managing conflict escalation.

The first aspect of Chinese airspace incursions is that they serve as psychological operations. The sheer volume and audacity employed in conducting hundreds of sorties in a relatively short period of time through the Taiwanese ADIZ demonstrates Taiwan’s inherent vulnerability to Chinese military power. At the same time, there is not much that Taiwan and its partners can do in response. Chinese aircraft flying through sovereign airspace, while a violation of international norms, are not sufficiently aggressive enough to merit a response, and a response that is viewed by the PRC as disproportionate would be used as a pretext for escalation and more severe actions in the future. Such sorties therefore cast doubt on Taiwan’s ability to resist the PRC and create reservations on whether or not Taiwan’s allies will provide sufficient assistance in an emergency. The threat of a PRC takeover monopolizes the discourse relating to that region, creating an atmosphere of fear and drowning out constructive narratives of the positive things that are taking place. While China would very much prefer to peacefully reunify with Taiwan, it has not ruled out kinetic operations, and the airspace incursions also serve to facilitate combat more easily.

With each airspace incursion, both Taiwan and Japan’s militaries enter a state of heightened alertness. Fighters must be scrambled to intercept the aerial interlopers and respond to any potential threats in the air. Such undertakings are profoundly expensive and taxing for personnel and resources. Command centers, observation units, and the aircraft and maintenance units are all mobilized into action with each ADIZ penetration. Japan has been forced to scale back its air policing posture, given how expensive Chinese incursions have become, and in 2020, it was estimated that 8.7% of Taiwan’s military budget was spent on responding to the airspace incursions. For China’s part, its advantage of manpower and resources means that it has an absolute advantage over both Taiwan and Japan and is quite capable of continually exhausting their airpower. Furthermore, continuous incursions without follow-up action will eventually dull Japanese and Taiwanese alertness. After having witnessed hundreds of violations without consequence, Japan and Taiwan may be lulled into a false sense of security, enabling the PRC to either create an environment of uncertainty in its operations or create the element of surprise if it so chooses to embark on a kinetic operation to reunify with Taiwan. Such gray zone operations also provide time and space for the PRC to conduct conventional force development. While Japan and Taiwan are expending their defense capabilities and losing balance, the PLA maintains a posture of comparative ease, able to focus on its 2027 goal of being militarily ready to take Taiwan by force if necessary.

On the surface, China’s violation of Japanese airspace appears to be a routine transgression, just another occasion of PRC provocations expressing the Chinese Communist Party’s displeasure at the current geopolitical situation. However, investigating more carefully reveals a concerted pattern of behavior designed to achieve a particular goal, namely, the reunification of Taiwan. The expansion of activities to Japan demonstrates that it has become inextricably linked to the Taiwan Strait dispute. Its constant opposition to China on regional issues, not just pertaining to Taiwan, but on the Quad, in which Japan maintains membership, and on the Senkaku Islands, which Japan controls but China disputes, has drawn the ire of the PRC. The entry of a PLAAF spy plane into Japan’s sovereign airspace is the manifestation of these frustrations, and timed to occur just before US National Security Advisor Sullivan’s visit to Beijing, represents a signal from the PRC. That is, while the PRC is amenable and open to negotiations, it maintains and cultivates several different avenues to pursue its goals, despite the risk of confrontation.

In response to the PLA’s aggressive gray zone activities, the United States, Japan, and Taiwan can only continue to improve and augment their defense capabilities. Effective synergy and innovative force multipliers will serve to narrow the gap in manpower and resources that the PLA presents and preserve readiness for any contingency that may arise. A strong network of alliances will enable the tyranny of distance to be mitigated, where the United States must surmount a great distance to provide effective assistance, and the smaller states in close proximity to the PRC will be able to efficiently respond to any exigency.

The views expressed are those of the authors and do not reflect the official position of the United States Military Academy, the Department of the Army, or the United States Department of Defense.